fn main() {
    println!("Hello, world!");
    let pair = (2, -2);
    println!("tell me about {:?}", pair);
    match pair {
        (x, y) if x == y =>
            { println!("These are twins"); }
        (x, y) if x + y == 0 =>
            { println!("Antimatter,Kaboom!"); }
        (x, _) if x % 2 == 0 =>
            { println!("The first one is odd"); }
        _ => println!("No correlation ...")
    }
}
